Table 1.
15 min, 60 min, and AUC blood glucose, plasma insulin, glucagon, ghrelin, GIP, GLP-1, PYY, total and essential amino acid concentrations, and the ratio of insulin to glucagon and HOMA-IR in healthy younger and older men.
| Younger | Older | |||||||
|---|---|---|---|---|---|---|---|---|
| Concentrations | Baseline | 15 min | 60 min | AUC | Baseline | 15 min | 60 min | AUC |
| HOMA index | 0.6 ± 0.1 | 0.5 ± 0.1 | ||||||
| Glucose (mmol/L) | 5.3 ± 0.1 | 5.3 ± 0.1 | 5.0 ± 0.1 #& | 312 ± 4 | 5.4 ± 0.1 | 5.4 ± 0.1 | 5.4 ± 0.1 #& | 323 ± 6 |
| Insulin (mU/L) | 2.6 ± 0.4 | 9 ± 1 +# | 13 ± 2 + | 824 ± 126 + | 2.3 ± 0.3 | 5 ± 1 +# | 12 ± 2 + | 593 ± 89 + |
| Glucagon (pg/mL) | 62 ± 7 | 94 ± 12 +#& | 133 ± 14 +& | 7541 ± 836 +& | 67 ± 4 | 79 ± 4 +#& | 119 ± 7 +& | 6514 ± 313 +& |
| Insulin to glucagon ratio | 0.04 ± 0.0 | 0.09 ± 0.01 +# | 0.10 ± 0.02 + | 5.1 ± 0.7 + | 0.04 ± 0.01 | 0.06 ± 0.01 +# | 0.08 ± 0.01 + | 4.1 ± 0.5 + |
| Ghrelin (pg/mL) | 1223 ± 101 | 1471 ± 153 + | 1235 ± 130 +# | 79,470 ± 8396 + | 1266 ± 120 | 1574 ± 207 + | 1313 ± 156 +# | 87,509 ± 12,176 + |
| GIP (pmol/L) | 13 ± 1 | 19 ± 3 + | 23 ± 1 +#& | 1458 ± 83 +# | 15 ± 2 | 27 ± 3 + | 34 ± 3 +#& | 2063 ± 185 +# |
| GLP-1 (pmol/L) | 26 ± 3 | 30 ± 3 + | 37 ± 3 + | 2023 ± 169 + | 23 ± 3 | 24 ± 3 + | 31 ± 4 + | 1675 ± 189 + |
| PYY (pmol/L) | 34 ± 4 | 37 ± 4 +# | 41 ± 5 + | 2276 ± 265 + | 26 ± 1 | 26 ± 1 +# | 36 ± 3 + | 1776 ± 115 + |
| Total amino acids (mmol/L) | 2.2 ± 0.01 | 2.6 ± 0.2 +& | 3.6 ± 0.2 +& | 236 ± 12 +& | 2.3 ± 0.01 | 2.4 ± 0.1 +& | 3.5 ± 0.1 +& | 225 ± 7 +& |
| Essential amino acids (mmol/L) | 0.7 ± 0.01 | 1.0 ± 0.04 +#& | 1.61 ± 0.13 +# | 106 ± 6 +& | 0.7 ± 0.01 | 0.8 ± 0.02 +#& | 1.52 ± 0.1 +# | 94 ± 5 +& |
Mean (±SEM) for 15 min, 60 min, and area under the curve (AUC) blood glucose, plasma insulin, glucagon, ghrelin, gastric inhibitory peptide (GIP), glucagon-like peptide-1 (GLP-1), peptide tyrosine-tyrosine (PYY), total and essential amino acids concentrations, and the ratio of insulin to glucagon and Homeostatic model assessment (HOMA) index in healthy younger (n = 10, n = 9 for GIP and GLP-1) and older (n = 10) men during intraduodenal infusions of saline (control) and whey protein loads of 30 kcal (7.5 g protein), 90 kcal (22.5 g protein), or 180 kcal (45 g protein). Main effect of protein load, age, and interaction effects were determined using a mixed-effect model with baseline concentrations as a covariate and post-hoc Bonferroni correction; statistical significance was accepted at p < 0.05. + p < 0.05 Effect of protein load. # p < 0.05 Effect of age. & p < 0.05 Interaction-effect of protein load by age.